Dual band monopole omni antenna

Abstract

A dual mode high-frequency printed circuit radar antenna for aircraft use having good aerodynamics is provided in the form of a printed circuit antenna molded into a smooth, blade-like protective shield. The antenna, printed on an epoxy glass substrate carried on a mounting plate including, integrated in series, a stub monopole element and a larger area capacitive loading member for I-band reception, an inductive member whose impedance is very high at I band and a monopole element which adds sufficient length that the entire conductor track acts as a quarter wave length monopole at C and D bands. At I band the stub monopole element and capacitive loading is isolated from the added monopole element by the high impedance inductive member, making for good I-band performance.

I claim: 
     
       1. A wide-band high-frequency antenna for reception over separated frequency bands including mounting and support means,   a coaxial connector fastened to said mounting and support means,   an upstanding member of dielectric material carried on said mounting and support means and a conductor track on the surface of said member constituting the radiating element of said antenna electrically connected to the center conductor of said coaxial connector including, connected in series, a highfrequency stub element, a capacitive loading member for said stub element at the higher of said frequency bands, an inductive member having very high impedance at the higher of said frequency bands and low impedance at the lower of said frequency bands, and a monopole element aligned with said stub, said capacitive element and said inductive element, the combined length of said elements being such as to provide a one-quarter wave length monopole antenna at the lower of said frequency bands.   
     
     
       2. A wide-band high-frequency antenna as set forth in claim 1 wherein said conductor track is a printed circuit on the surface of said dielectric member. 
     
     
       3. A wide-band high-frequency antenna as set forth in claim 1 wherein said high-frequency stub and said capacitive member constitute a pseudo quarter-wave monopole section with capacitive loading at the higher of said frequency bands. 
     
     
       4. A wide-band high-frequency antenna as set forth in claim 1 wherein said inductive member effectively isolates said monopole element from said stub and said capacitive loading member at the higher of said frequency bands. 
     
     
       5. A wide-band high-frequency antenna for reception over two separated frequency bands adapted to be mounted on an external surface of a vehicle including a mounting flange for attaching said antenna to said surface, a coaxial connector attached to said flange,   an upstanding member of thin deielectric material supported on said flange and a printed circuit conductor track on the surface of said member constituting the radiating element of said antenna including, connected in series, a high-frequency stub element vertically from said flange and connected to the center conductor of said coaxial connector, a capacitive plate element connected to said stub element, an inductive element comprising a very narrow straight conductor having very high impedance at the higher of said frequency bands, and an additional monopole element aligned with said stub element, said plate and said inductive section and connected to said inductive section, the combined length of said elements being such as to provide a one-quarter wave length monopole antenna at the lower of said two frequency bands.   
     
     
       6. A wide-band high-frequency antenna as set forth in claim 5 wherein a blade-shaped protective cover of dielectric material is placed over said dielectric member and fastened to said mounting flange.